Secondary security key update in wireless networks

Abstract

A user equipment (UE) receives secondary security key update information for one or more candidate cells for secondary cell group (SCG) primary secondary cell (PSCell) change. UE receives a cell switch command for a secondary cell group (SCG) PSCell change and performs the cell switch from a serving cell to a target cell. For the target cell, UE performs a security key update based on the secondary security key update information. UE receives a secondary security key update identifier for each candidate cell and maintains a variable to store a secondary security key update identifier for the serving cell. If the secondary security key update identifier of the target cell is different from that of the serving cell, UE performs a security key update for the cell switch.

What is claimed is: 
     
         1 . A user equipment (UE) for facilitating communication in a wireless network, the UE comprising:
 a transceiver configured to:
 receive, from a serving cell, secondary security key update information for one or more candidate cells for secondary cell group (SCG) primary secondary cell (PSCell) change; and 
 receive, from the serving cell, a cell switch command indicating that a cell switch from the serving cell to a target cell among the one or more candidate cells is triggered, wherein the target cell is associated with a secondary cell group (SCG); and 
   a processor operably coupled to the transceiver, the processor configured to:
 perform the cell switch from the serving cell to the target cell for the SCG; and 
 perform a security update for the target cell based on secondary security key update information associated with the target cell. 
   
     
     
         2 . The UE of  claim 1 , wherein:
 the transceiver is further configured to:
 receive, from the serving cell, a secondary security key update identifier for each candidate cell; and 
   the processor is further configured to:
 maintain a variable to store a secondary security key update identifier for the serving cell; and 
 perform the security update based on a determination that a secondary security key update identifier of the target cell is different from the secondary security key update identifier for the serving cell stored in the variable. 
   
     
     
         3 . The UE of  claim 2 , wherein the processor is further configured to replace the secondary security key update identifier stored in the variable with the secondary security key update identifier of the target cell. 
     
     
         4 . The UE of  claim 1 , wherein:
 the transceiver is further configured to receive a list of secondary security key update information including one or more entries, each entry comprising a secondary security key update identifier and an associated secondary key (SK) counter; and   the processor is further configured to store the list of secondary security key update information.   
     
     
         5 . The UE of  claim 4 , wherein the processor is configured to perform the security update based on an SK counter in a predetermined entry or an entry indicated by a secondary security key identifier associated with the target cell. 
     
     
         6 . The UE of  claim 5 , wherein the processor is further configured to remove the predetermined entry or the entry indicated by the secondary security key identifier associated with the target cell from the stored list of secondary security key update information. 
     
     
         7 . The UE of  claim 1 , wherein:
 the cell switch command includes a secondary security key update identifier associated with the target cell; and   the security update is performed based on secondary security key update information identified by the secondary security key update identifier.   
     
     
         8 . The UE of  claim 1 , wherein:
 the secondary security key update information associated with the target cell is included in the cell switch command; and   the secondary security key update information includes a secondary security key update request indication or an SK counter.   
     
     
         9 . A method performed by a user equipment (UE) in a wireless network, the method comprising:
 receiving, from a serving cell, secondary security key update information for one or more candidate cells for secondary cell group (SCG) primary secondary cell (PSCell) change;   receiving, from the serving cell, a cell switch command indicating that a cell switch from the serving cell to a target cell among the one or more candidate cells is triggered, wherein the target cell is associated with a secondary cell group (SCG);   performing the cell switch from the serving cell to the target cell for the SCG; and   performing a security update for the target cell based on secondary security key update information associated with the target cell.   
     
     
         10 . The method of  claim 9 , further comprising:
 receiving, from the serving cell, a secondary security key update identifier for each candidate cell;   maintaining a variable to store a secondary security key update identifier for the serving cell; and   performing the security update based on a determination that a secondary security key update identifier of the target cell is different from the secondary security key update identifier for the serving cell stored in the variable.   
     
     
         11 . The method of  claim 10 , further comprising replacing the secondary security key update identifier stored in the variable with the secondary security key update identifier of the target cell. 
     
     
         12 . The method of  claim 9 , further comprising receiving and storing a list of secondary security key update information including one or more entries, each entry comprising a secondary security key update identifier and an associated secondary key (SK) counter. 
     
     
         13 . The method of  claim 12 , further comprising performing the security update based on an SK counter in a predetermined entry or an entry indicated by a secondary security key identifier associated with the target cell. 
     
     
         14 . The method of  claim 13 , further comprising removing the predetermined entry or the entry indicated by the secondary security key identifier associated with the target cell from the stored list of secondary security key update information. 
     
     
         15 . The method of  claim 9 , wherein:
 the cell switch command includes a secondary security key update identifier associated with the target cell; and   the security update is performed based on secondary security key update information identified by the secondary security key update identifier.   
     
     
         16 . The method of  claim 9 , wherein:
 the secondary security key update information associated with the target cell is included in the cell switch command; and   the secondary security key update information includes a secondary security key update request indication or an SK counter.   
     
     
         17 . A base station (BS) for facilitating communication in a wireless network, the BS comprising:
 a transceiver configured to:
 transmit, to a user equipment (UE), secondary security key update information for one or more candidate cells for secondary cell group (SCG) primary secondary cell (PSCell) change; and 
 transmit, to the UE, a cell switch command indicating that a cell switch from a serving cell of the BS to a target cell among the one or more candidate cells is triggered, wherein the target cell is associated with a secondary cell group (SCG), 
   wherein secondary security key update information associated with the target cell is used for a security update for the target cell.   
     
     
         18 . The BS of  claim 17 , wherein the transceiver is further configured to:
 transmit, to the UE, a secondary security key update identifier for each candidate cell.   
     
     
         19 . The BS of  claim 17 , wherein the transceiver is further configured to:
 transmit, to the UE, a list of secondary security key update information including one or more entries, each entry comprising a secondary security key update identifier and an associated secondary key (SK) counter.   
     
     
         20 . The BS of  claim 17 , wherein:
 the cell switch command includes a secondary security key update identifier associated with the target cell; and   the security update is performed based on secondary security key update information identified by the secondary security key update identifier.